Atlantic Technology SP-8000 instruction manual Phase Control, Parametric Room Equalizer EQ

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Setup 11

Instruction Manual

to Large the processor/receiver assumes that they can produce full fre- quency range sound,including very deep bass at fairly high volume levels. When set to Small it assumes that the speakers are bass limited and feeds the bass from that channel to the subwoofer. If your processor/receiver offers this choice, all Atlantic Technology satellite speakers should be set to Small, regardless of their actual size.

For those of you who may have heard otherwise, the choice of Large or Small is not a matter of opinion, preference, taste, or based upon the phases of the moon. So please ignore any and all free and helpful (and many times incorrect) advice and set them to Small. In fact, the vast majority of speakers on the market today should be set to small.As a rule of thumb, if any satellite speaker in your system doesn’t have a 10-inch or larger woofer, it most probably should be set to Small, as far as Bass Management is concerned.

The PHASE Control

A subwoofer operating out of phase with the rest of

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woofer is provided on the SP-8000. It has 4 positions (0°,90°,180°,270°) for added flexibility. To set the PHASE control, insert the supplied Atlantic Technology/Sencore Test and Training CD in your CD/DVD player and select the broadband bass test tones on Track 16. Have someone sit in the prime listening position to evaluate the sound. Pay particular attention to the tran- sition of bass from the subwoofer to the satellite speakers.

You can also listen to a musical source such as a CD or DVD, with strong bass content that spans the range from deep bass to mid bass (a well recorded jazz disc with someone playing a full stand up bass is always a good choice). It’s best not to use a“one note” special effects track like a big explosion or dinosaur stomping to test the subwoofer.Experiment with the position of the PHASE control(s) to get the best transition from sub to sat- ellites. It should be fairly obvious which is the correct setting.In particular, there will be a smoother, more integrated transition between the satellites and the subwoofer when they are properly phased.

Adjusting the Room EQ Using a Meter or Real Time Analyzer (RTA)

IMPORTANT NOTE: During all set up operations except setting the Phase control it will be beneficial to shut off or disconnect all the speakers except the Subwoofer.

It’s important to complete the preceding steps regarding speaker setup before adjusting the parametric room equalizer. Once they’re complete, insert the Atlantic Technology/Sencore Test and Training CD into your CD or DVD player and go to Track 16, which is a full range test signal including all bass frequencies from 20Hz to 120Hz. Set the BASS LEVEL of your SP-8000 for approximately 75dB at the primary listening position. If you are using an RTA, set it to at least 1/6th octave resolution and slow response (Use slow response to allow the meter to average the standing waves that build up in the room).Continue using Track 16 to observe the overall response of the subwoofer. It is highly likely that you will find at least one significant peak (between 20Hz and the crossover point set on the amplifier or in the processor).Write down the center frequency of the peak, how wide the peak is (by noting the upper and lower frequencies where it starts and stops) and how large it is, in dB.

FREQUENCY			WIDTH	ATTENUATION		Begin setting the para-
						metric EQ by adjusting
	75		1.0		-10
						the FREQUENCY control
25	125	0.2	1.5	-20	0db	to the approximate center
						frequency of the peak.Next
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						adjust the WIDTH control

to the approximate width of the peak. Note that the WIDTH control is calibrated in octaves. An octave is a doubling or halving of any chosen frequency.For example,if the chosen frequency is 40Hz,1 octave higher would be 80Hz, and one octave lower would be 20Hz. Since the WIDTH control ranges from 0.2 octave to 1.5 octaves you see that you can adjust from a fairly narrow band to a fairly wide band on either side of the center frequency.Next,set theATTENUATION control to the approximate minus dB value to compensate for the peak. Measure the bass response again and see how much you have reduced the overall peak.You may need to fine-tune the controls to smooth the response as much as possible.

Parametric Room Equalizer (EQ)

In order to optimize the performance of your subwoofer the parametric room equalizer should be utilized. The built in Room EQ allows you to select the frequency you want to adjust, and how wide a band on either side of that frequency you’re going to adjust with it. It is designed spe- cifically to remove (turn down) unwanted peaks in the bass. The proce- dure is fairly simple: the included Atlantic Technology/Sencore Test and Training CD is used along with a SPL meter to define the single largest bass peak at the prime listening position and then reduce it with the Room EQ.

The test and setup CD also includes a wealth of general information concerning sound reproduction and home theater, in addition to the test tones. Although the test tones can be used to set the Room EQ “by ear” we very strongly recommend using a Sound Pressure Level meter or a Real Time Analyzer to set the Parametric EQ.

Setting the Parametric EQ Using an SPL Meter

If you only have an SPL meter, set the meter to C Weighting and Slow response. Set the Bass Level of your SP-8000 for approximately 75dB at the listening position as outlined above using Track 16 of the test disc. Sit in the prime listening position with a pencil and paper. Play Tracks 1-15 sequentially to measure the subwoofer response.Take enough time with each measurement to allow the meter to stabilize. Write down the measured level for each frequency, covering the range from 20Hz to the crossover point selected on the subwoofer amplifier or in the receiver/ processor. Once again, you will most likely find one or more significant peaks in the bass response.Proceed as detailed above to reduce the larg- est peak as much as possible.